FORM TWO PHYSICS
A 2019 FELIX LISAUSYO PRODUCTION
FELIX LISAUSYO
YOUR FRIEND WHEN IT COMES TO GATHERING MATERIALS FOR MSCE EXAMINATIONS
FELIX LISAUSYO 2019 PRODUCTIONS
TOPICS COVERED
Scientific investigation
Strategies of planning an investigation
The structure of a scientific investigation
A sample scientific investigation
Thermal expansion
Thermal expansion and contraction
Effects of thermal expansion.
Application of thermal expansion.
Density
Density
Comparison of densities of solids, liquids and gases
Effects of temperature on density
Unusual expansion of water between 0
o
C and 4
o
C
Floating and sinking
Average density
Specific heat capacity
Heat capacity
Comparison of specific heat capacity of the three states of matter
Application of specific heat capacity
Heat transfer
Heat and temperature
Modes of heat transfer
Conduction
Comparing rates of conduction in metals
Convection
Radiation
Application of heat transfer
Power and machines
Power
Machines
Electronics
Electronics
Electrostatic charging by rubbing
Source of electronic charging
The law of charges
Electric field and electric field patterns
Effects and application of electronics
Light
Rectilinear propagation of light
Formation of shadows and eclipses
Pinhole camera
Reflection on a plane surface
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Rotation of a plan mirror
Parallel mirrors
Mirrors inclined at an angle
Application of reflection at plane surface
Refraction of light
Simple experiments to illustrate refraction of light
Real and apparent depth
Refraction of light through a prism
Dispersion of white light
Introduction to nuclear physics
Structure of an atom
Isotopes
Radioactivity
Radioactive decay and half life
Types of radiations emitted and their properties
Dangers of radioactivity
Applications of radioactivity.
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UNIT ONE
SCIENTIFIC INVESTIGATION
SKILLS REQUIRED TO DEVELOP FOR SOME ONE TO CARRY OUT
SCIENTIFIC INVESTIGATIONS
Making an observation
Involves critically looking at a natural phenomena as they take place.
Proposing a hypothesis
A hypothesis is an idea that is suggested as a possible explanation or answer to
the observed problem.
Designing an experiment to test the hypothesis
Identify the variables
Controlled variables
Are variables kept constant so that they do not interfere with
the results.
Independent variables
Are variables you control as you wish within suitable ranges of
the investigation.
Dependent variables
Are all variables you measure every time you change your
independent variables.
Outline the apparatus and procedure or method to be followed.
Methods of data presentation
This includes
drawing tables to show the quantities being measured and their units of
measurements
drawing graphs
drawing bar charts etc
Drawing conclusion from the investigation
It involves comparison of the hypothesis and the results of the investigation.
This comparison makes you accept or reject the hypothesis.
Evaluating the strength of the evidence
You indicate what could be source of the limitations of hypothesis if accepted.
If not accepted, come up with another hypothesis and investigation.
STRATEGIES OF PLANNING AN INVESTIGATION
Safety measures
Required to be followed when carrying out an investigation successfully.
It includes the hard factors in case of apparatus and chemicals.
The apparatus and chemicals to be used
Should be appropriate for the measurement of quantities involved.
Should have correct scale and range of values.
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In case of chemicals with precautions, follow the precaution measures as
stipulated on the container of the chemicals.
Be conversant on how the apparatus can be operated and used.
The procedure or method
Clearly show the steps to be followed when conducting the investigation.
Indicate quantities which will be varied and vary at will.
Show how each quantity will be measured.
Indicate the value of the quantity that will be kept constant.
Repeated readings
This is done to improve the reliability of the results obtained.
Finding the average of the repeated results reduces experimental error.
THE STRUCTURE OF A SCIENTIFIC INVESTIGATION
Aim of the experiment
Is a belief and concise statement of the objective of the experiment.
Is derived from the hypothesis initially stated.
Apparatus/equipment to be used
Include all materials to be used.
These are identified and listed here.
Procedure/method
Is a section of step-by-step account of what is to be done.
You also indicate it will be done.
A well labelled diagram of the set-up should be included.
Quantities to be varied, measured, kept constant should be indicated clearly
with their values.
A statement on how the results will be analysed should be included.
Results
Results of measurements are shown here.
These include graphs, chart and tables.
Analysis
Is where the result of the investigation are discussed.
The usual points of discussion are
Trend of the graph
Explain why the graph curve decreases, increases or straight
line.
The gradient of the graph
Relate the quantities you are investigating with the gradient of
the graph where possible.
Area under the graph
It may sometimes be related to the quantity of investigation in
some way.
Conclusion
You state carefully the results analysed.
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Indicate limitations of the investigation you carried out.
Sources of errors must be indicated.
Also give areas that require improvement
It should finally discuss the extent to which the hypothesis (aim) has been
achieved.
SAMPLE SCIENTIFIC INVESTIGATION
This should base on the observation made in a community.
Observation
If a student observed that a bottle filled with water and closed tightly placed in
the fridge breaks as the water freezes
From this observation one can come up with the hypothesis.
Hypothesis
Water expands when turns to ice and occupies a greater space than when it is
liquid.
Experimentation
Aim
To show that water expands when it freezes and becomes ice.
Apparatus
Two identical glass bottles e.g. 25ml bottles
Refrigerator
Water.
Procedure
Fill the two glass bottles with 25ml of water at room temperature.
Put the two bottles in the fridge, one in the freezer compartment while
the other in the cooling compartment.
Close the fridge and allow the bottles be in the fridge over a night.
Remove the two bottles and observe what happens.
Results
The water level in the bottle placed in cooling compartment is lower
than before.
The water level in the bottle in the freezing compartment increases
and the bottle may break due to expansion of water.
Analysis of the results
Since no water was added, and the increase in level of water in one
bottle whose water frozen is an indication that water expanded when
freezing.
Conclusion
The results I found are similar to the hypothesis. Therefore, water
expands when freezing.
Strength and weaknesses
The strength is that the experiment was conducted only for water
which is easy to compare the findings from two bottles.
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It weakness is that it does not give evidence that other liquid scan
behave in the same way since they were not tried.
Possible sources of error in students
Parallax errors
Occurs when the eye is not well positioned when reading the volume
of the water in the measuring cylinders.
To minimize this, one should place the eye in the same horizontal level
of the lowest point of the meniscus of the water in the measuring
cylinders and read the readings.
The correct level of the eye is B.
A
B
C
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UNIT TWO
THERMAL EXPANSION
EXPANSION
Is the increase in size of the substance when heated
The increase magnitude and direction depends on the type of substance and amount of
heat applied to it.
CONTRACTION
Is the decrease in size of the substance when cooled.
Every substance has its own rate of expansion except for gases.
EXPANSION AND CONTRACTION IN SOLIDS
All solids expand when heated.
The rate of expansion varies with different solids.
DEMONSTRATING EXPANSION CONTRACTION IN SOLIDS
ACTIVITY ONE
Aim
To demonstrate expansion and contraction using thin metal rod
Apparatus
Thin metal rod
Rollers connected to a pointer
Source of heat
G-clamp
Procedure
Clamp one end of the long thin metal rod tightly with end of the rod resting on
a roller fitted with a thin pointer as shown below.
Heat the metal rod for some time and observe what happens to the pointer.
Remove the burner and allow the rod to cool and observe what happens to rod.
Clamp Pointer fixed to roller
Thin metal rod
Roller
Table Smooth surface
Heat
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Repeat the experiment with thin metal rods of different materials and observe
what happens.
Observation
The pointer deflects in the clock wise direction when the rod is heated and
anticlockwise when the rod is being cooled.
The pointer deflects differently with different types of metals.
Discussion
When metals are heated, they increase in length.
This increase in length makes the roller to roll hence making pointer deflects.
Upon cooling, the metal decreases in size hence makes the roller again to roll
and makes the pointer deflect anticlockwise.
Conclusion
Solids expand when heated and contract when cooled.
Different solids expand and contract differently.
ACTIVITY TWO
Aim
To demonstrate expansion and contraction using the bar and gauge apparatus.
Apparatus
A bar and gauge apparatus. (This is a bar with a suitable wooden handle and
gauge of which a bar fits into the gauge at room temperature)
Bunsen burner
Procedure
Move the metal bar into and out of the gauge at room temperature and observe
what happens.
Keep the metal bar a way from gauge and heat the bar for some time.
Try to fit the bar into the gauge and observe what happens.
Allow the bar to cool and try to fit it into the gauge and observe.
Observation
At room temperature, the bar fit exactly into the gauge.
After the bar is heated, the metal bar does not fit into the gauge. It is larger.
The metal bar again fits exactly when cooled.
Discussion
When the bar is heated, there is an increase in length than before hence it does
not fit in.
When cooled, the bar goes to its original size hence fits well.
Conclusion
Solids expand when heated and contract when cooled.
ACTIVITY THREE
Aim
To demonstrate expansion and contraction of solids using the ball and ring
apparatus.
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Apparatus
A ball and a ring
Bunsen burner
A bowl of cold water
Procedure
Arrange the setting as shown below.
Move the ball in and out of the metal ring at room temperature
Keep the metal ball away from the ring and heat it for some time.
Try to pass the ball through the metal ring and record your observation.
Cool the metal ball again in a bowl of cold water and try to pass the ball
through the ring and record your observation.
Observation
At room temperature, the metal ball passes through the ring.
When the ball is heated, it does not pass through the metal ring.
When it is cooled, it passes through it easily.
Discussion
When metal ball is heated it expended. There was an increase in volume and
the ball could not pass through the metal ring.
When the metal ball was cooled, it contracted and gained the original volume
which makes it to pass through the metal ring easily.
Conclusion
Solids expand when heated and contract when cooled.
WHY DO SOLIDS EXPAND WHEN HEATED?
When solids are being heated, the molecules start to vibrate with large amplitude on a
fixed position.
This makes them to collide with each other hence move far apart.
As the distance between the molecules increase, the volume also increase.
EXPANSION OF LIQUIDS
All liquids expand when heated.
Expansion do differ at the same temperature.
Metal ball
Metal ring
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INVESTIGATION TO DEMONSTRATE EXPANSION OF LIQUIDS
Aim
To demonstrate expansion of liquids
Apparatus
A glass flask
Long narrow glass tubing
Coloured water
Tripod stand
A rubber stopper
Bunsen burner
Wire gauze
Procedure
Fill a glass flask with coloured water.
Fit the flask with rubber stopper carrying long narrow glass tubing.
Mark the initial level of water in the glass tube before heating.
Heat the water in the flask and observe the level of water in the glass tube.
Observation
The level of water after heating was higher than the level of water before
heating.
Discussion
When heating, the glass flask expands and the level of water drops first.
When heating continued, the level of water started to increase.
When the water was allowed to cool down, the level of water went down to its
initial level
Conclusion
Liquids expand when heated and contract when cooled.
Glass tube
Level after heating
Level before heating
Coloured water
Heat
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WHY LIQUIDS EXPAND ON HEATING
Molecules in liquids are closely compacted but can slide on one another.
When heated, the gain extra kinetic energy which makes them to move far apart.
This makes the volume to increase.
EXPANSION OF GASES
Gas also expand when heated.
Gases have equal expansion rate.
INVESTIGATION TO DEMONSTRATE EXPANSION OF GASES.
ACTIVITY ONE
Aim
To demonstrate the expansion of air.
Materials
A thin glass flask
A long narrow glass tube
A rubber stopper
Procedure
Take a thin glass flask opened on top.
Close the flask with the rubber stopper carrying a long narrow tube.
Invert the flask so that the glass tube dips into the water in a container and
record your observation.
Place your hands over the flask to warm it for some time and observe what
happens .
Remove your hands from the flask and wait for some time and observe what
happens.
Observation
The water level rises from the glass flask to the narrow glass tube dipped in
water.
When the flask is warmed, the level of water in the tube drops and some
bubbles are seen escaping from the flask through the tube.
On removing the hands from the flask, water level rises the glass tube again.
Discussion
Thin glass flask
Air
Narrow long tube
Bubbles Coloured water
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Water level in the glass tube drops because of the expansion of the air in the
glass flask when warmed.
When cooled, the water level rises up the glass tube.
Conclusion
Gases expand when heated and contract when cooled.
ACTIVITY TWO
Aim
To demonstrate the expansion of gases.
Materials
Glass bulb with air inside.
A metre rule in vertical position
A reservoir with mercury
Steam
Glass jacket
Procedure
Set up the apparatus as shown below.
Calculate water at 0
o
C through the jacket and adjust reservoir so that the level
of mercury is the same both sides.
Measure the volume of air (gas) in the bulb.
Pass the steam through the jacket until the temperature is constant.
Adjust the level of mercury in both sides until they are the same and measure
the volume of air in the bulb.
Observation
When passing the cold water at 0
o
C, the volume of the air in the bulb reduces.
The volume of air increases on passing the steam through the glass jacket.
Discussion
The volume of air reduces when cold water is passed through due to
contraction.
The volume of air increased when the steam is passed though due to
expansion.
Conclusion
Gases expand when heated and contract when cooled.
Steam Reservoir
(mercury)
Gas Metre ruler
Bulb
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EFFECTS OF THERMAL EXPANSION
Force produced due to expansion and contraction can
make metals to bend
make building to crack
make glass bottle full of water when frozen breaks
make railway lines to bend
make the egg shell to break
APPLICATION OF THERMAL EXPANSION
Led to the development of thermostats used as automatic switches in electrical
appliances.
Industries use hot rivets when joining the steel plates together, when cooling, the
force of contraction pulls the plates firmly together.
Metal pipes carrying steam are joined using expansion joints (loops) which allow the
pipes to expand or contract easily when steam or hot water passes through them or
when pipes cool down.
Telephone and electric cables are loosely connected to give room for contraction.
Surveyors measuring tapes are made up of alloys (iron and nickel called invar) so that
there should be a very small change in length due to changes in temperature.
Expansion channels are made in concrete roads or when making cemented floors of
buildings to give room for expansion during hot days.
Construction at the end of concrete bridges has steel metals resting on rollers so that it
should not be affected when contracting and expanding.
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UNIT THREE
DENSITY
DENSITY
Is define as the quotient of mass and its volume.
i.e. density =
When the volume is increased, the density is reduced and when the mass of the
substance increases, the density increases
So, it can be defined as mass per unit volume.
Density is the derived quantity.
SI unit for density is
.
DETERMINING DENSTIES OF SOLIDS
DENSITY OF REGULAR OBJECTS
Find the mass using a balance.
Measure its dimensions and multiply them to find volume.
Divide the volume into the mass.
DENSITY OF IRREGULAR OBJECTS
Find the mass using a balance.
Use liquid to find its volume using the principal that the displaced amount of water is
equal to the volume of the solid.
Pour the water in the measuring cylinder and record its volume.
Immerse in the irregular solid and record the new volume.
Subtract the first volume before the solid was immersed from the second
volume after immersing the solid. This will give you the volume of the solid.
Divide the mass by the volume.
DETERMINING THE DENSITY OF LIQUIDS
Measure the mass of the clean container.
Pour in the known volume of liquid and measure its mass.
Subtract the mass of the empty container from the mass of container plus liquid. This
gives the mass of the liquid.
To find the volume, use the measuring cylinder.
Divide the mass by the volume.
DETERMINING DENSITY OF GASES
Find the mass of deflated balloon or plastic paper.
Inflate it and find the new mass.
Subtract the mass of deflated container from the inflated container.
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To find the volume use the measuring cylinder,
Fill it with water and put it upside down.
Connected the inflated balloon to it and record the volume of water displaced.
This is the volume of the gas inflated in.
Divide the mass by the volume.
DETERMINING DENSITY OF AN ALLOY
An alloy is the metallic substance made by melting two or more types of metals
together in a controlled proportion.
In this case, you add the masses of the combined metals and add the volumes of the
combined metals.
Divide the total mass by total volume.
COMPARISON OF DENSITIES OF SOLIDS, LIQUIDS AND GASES
Solids have highest densities because their particles are closely compacted hence have
greatest masses.
They are followed by liquids since particles are also closely packed but with loose
connection.
Gases have the least densities because particles are always in motion.
EFFECT OF TEMPERATURE ON DENSITY OD A SUBSTANCE
Density is defined as mass per unit volume.
When the substance is heated, the volume increases with no change in mass.
When this mass is divided by the new larger volume, the quotient is lowered.
Hence increase in temperature decreases the density.
However, cooling the substance reduces the volume due to contraction.
This increases the density of the substance.
Most liquids expand steadily on heating.
Water behaves in an unusual (abnormal) manner.
When water is heated above 0
o
C, temperature rises up to 4
o
C without changing its
volume.
EFFECTS OF ANOMALOUS EXPANSION OF WATER
Above 4
o
C, volume starts to increase like other liquids.
Between 0
o
C to 4
o
C. Water shows abnormal behaviour (unusual) called unusual
expansion of water.
Thus a fixed mass of water has a minimum volume at 4
o
C.
Volume
4
o
C
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From the graph it is seen that a fixed mass of water is minimum at 4
o
C.
That’s where the water has the minimum density.
1. Survival of aquatic organisms in freezer of lakes and ponds.
The maximum density of water is at 4oC.
Anything above or below 4oC becomes less dense.
The frozen water becomes less dense hence floats on top.
This makes the bottom water still at liquid state.
2. Bursting of water pipes.
When water is below 4oC, it starts to freeze and expands.
This expansion increases the volume and cannot fit into the pipes hence pipes
break.
3. Weathering of rocks.
When water freezes in the rock cracks, it expands hence increasing the crack
of the rock.
This results into breaking of the rock (weathering).
4. Floating and sinking.
When bodies have higher densities than that of water, they sink in water.
When they have equal or lower densities than that of water, they float on
water.
Density
4
o
C
Temperature
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APPLICATION OF FLOATING AND SINKING IN RELATION TO DENSITY
Development of large machines which float of water. They are made in such a way
that the average density should be lower than that of water.
Submarine is made with a reserve of air bag to be used when they want it to float to
reduce its density to that of water.
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UNIT FOUR
SPECIFIC HEAT CAPACITY
HEAT
Is the form of energy which passes from the body of high temperature to the body of
low temperature.r
The SI unit of heat is joule (J).
HEAT CAPACITY
Is the quantity of heat energy required to change the temperature of the substance by 1
kelvin.
Heat capacity varies direct proportional to the change in temperature.
Heat capacity =
The SI unit of heat capacity is joule per kelvin
Examples
200j of heat energy is needed to change the temperature of a given mass of water from
25
o
C to 34
o
C. How much heat energy is needed to change temperature of this mass of
water from 20
o
C to 48
o
C?
Solution
Initial temperature change was (34 – 20)
o
C = 14
o
C
Final temperature change was (48 -20)
o
C = 28
o
C
If 14
o
C used the heat energy (Q) of 200j
28
o
C can used more energy
Q =
=
= 400j.
Exercise
Calculate the quantity of heat required to raise the temperature of a metal block of
capacity of 520j/k from 9
o
C to 39
o
C.
The quantity of heat required to raise the temperature of water from10
o
C to 65
o
C is
6200j. Calculate the heat capacity of water.
SPECIFIC HEAT CAPACITY
Is the heart energy required to change the temperature of a substance of mass 1 kg by
1 kelvin.
Specific heat capacity (C) =
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C =
Q = mC
The SI unit of specific heat capacity is joule per kilogram per kelvin (J/kgK).
Exercise
Calculate the heat energy required to raise the temperature of 2.5kg of aluminium
from 20
o
C to 40
o
C if the specific heat capacity of aluminium is 900J/knK.
18000J of heat is supplied to raise the temperature of a solid of mass 5kg from 10
o
C
to 50
o
C. Calculate the specific heat capacity of the solid.
Find the final temperature of water if 12000J of heat is supplied by heater to heat
100g of water at 10oC if specific heat capacity of water is 4200J/kgK.
NB
Solids have highest specific heat capacities because they require a lot of energy to
melt them.
This is followed by liquids then gases.
SPECIFIC HEAT CAPACITIES OF SOME SUBSTANCES
SOLIDS
LIQUIDS
SUBSTANCE
SPECIFIC HEAT
CAPACITY (J/kgK)
SUBSTANCE
SPECIFIC HEAT
CAPACITY (J/kgK)
Aluminium
900
Castor oil
2130
Brass
370
Coconut oil
2400
Copper
390
Glycerol
2400
Cork
2000
Mercury
140
Glass
670
Olive oil
2000
Ice
2100
Paraffin oil
2130
Iron
460
Sulphuric acid
1380
Lead
130
Water
4200
Silver and tin
230
Sea water
3900
APPLICATION OF SPECIFIC HEAT CAPACITY
Materials with high specific heat capacity absorbs a lot of heat energy with small raise
in temperature. This makes water to be used in car radiators and hydrogen gas
enclosed in electric generator.
Materials with low specific heat capacity are quickly heated up and experience big
change in temperature. They are uses in making cooking utensils.
Sensitive thermometers are made from materials with low specific heat capacity in
order to detect even small amount of heat energy supplied with its change in
temperature.
Materials with high specific heat capacity are used in making handles of heating
devices such as pans.
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Water taken by human being is used to regulate the temperature of the body since it
has high specific heat capacity.
Sea water has little change in temperature during the day and night because it has high
specific capacity. Cold during the day and warm during the night.
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UNITY FIVE
HEAT TRANSFER
HEAT
Is the form of energy which passes from the body of high temperature to the body of
low temperature.
The SI unit of heat is joule (J).
TEMPERATURE
Is the degree of coldness or hotness of the body.
Kinetic Theory of Matter states that particles of matter are always in motion.
Temperature can be defined as a measure of the average kinetic energy of the
molecules of a substance.
The SI unit for temperature is Kelvin(K).
But the common measure of temperature is in degrees Celsius (
o
C).
DIFFERENCES BETWEEN HEAT AND TEMPERATURE
Heat is a form of energy while temperature is the degree of hotness and coldness.
Heat is measured in joules (J) while temperature is measured in degrees Celsius (
o
C).
MODES OF HEAT TRANSFER
Conduction
Convection
Radiation
CONDUCTION
Is the transfer of heat through solids.
Conduction occurs from region of high temperature to the region of low temperature.
There is no visible movement of the heated particles.
FACTORS AFFECTING HEAT TRANSFER THROUGH CONDUCTION
Temperature differences.
Heat energy in solids flow due to differences in temperature. The higher the
temperature difference, the higher the energy flow.
Material differences.
Different materials conduct heat at different rates.
Thickness/ cross section
Thick materials conduct heat faster than thin materials.
Length/size differences.
Short materials conduct heat faster than long materials.
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Duration of heating.
Time taken to heat the material will determine how much heat is conducted
though the material.
TYPES OF CONDUCTORS
Good conductors
Poor conductors
GOOD CONDUCTORS
All materials which allow heat to pass through them easily. Most of these are metals.
These conduct heat with different rates.
POOR CONDUCTORS
All materials which have poor ability to transfer heat through them. Examples of these
include water, air, wood, plastics, papers etc.
RELATIVE CONDUCTIVITIES
Different substances at room temperature conduct heat differently.
The conductivity of heat in air at room temperature is said to be 1.
The heat conduction of different substances related to heat conduction in air at room
temperature is called relative conductivity.
Some of the relative conductivities are as follows;
SUBSTANCE
CONDUCTIVITY
SUBSTANCE
CONDUCTIVITY
Air
1
Mercury
270
Wood
6
Iron
3000
Cardboard
8
Brass
4500
Brick
23
Aluminium
8000
Water
25
Copper
16000
Glass (window)
35
Silver
18000
CONVECTION
Is a mode of heat transfer through fluids by actual physical movement of molecules of
the fluids due to temperature differences within the fluid.
Convection occurs from bottom going up the container of the fluid.
Example; When water is boiling, it starts from down going up.
APPLICATION OF CONVECTION
Fixing of windows in buildings uses air convection.
Natural convection currents over the earth’s surface.
Sea breeze
During the day, the temperature of the land rises faster than the
temperature of the sea water.
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The air over the land becomes warmer than the air over the sea water.
The warm air of less dense rises from the land allowing the cold air
over the sea to blow to the land.
This movement of cold air from the sea to the land is called sea breeze.
Land breeze
During the night, the land cools faster than the sea water.
Warm air from the sea rises up.
The denser air from the land moves to the sea makes the land become
warm.
This movement of cool air from the land to the sea is called land
breeze.
Electrical devices
They have their heating coil at the bottom.
The refrigerators have their freezing unit at the top.
RADIATION
Movement of heat in energy through the vacuum.
Is the heat transfer that does not affect the intermediate medium
Heat transfer from the sun uses radiation.
The heat that is being transferred is called radiant.
Amount of heat energy radiated depends up temperature of the body.
FACTORS AFFECTING RADIATION
Temperature of the body.
Increase in temperature increase amount of energy radiated.
Colour of the body.
Dull colours such as black absorb more heat energy than bright colours such
as white.
Type of conductor.
Bad conductors are good absorbers and good emitters while good conductors
are poor absorbers and poor emitters.
APPLICATION OF HEAT TRANSFER
Construction of vacuum flasks.
Construction domestic hot water system.
Extraction of solar energy.
Construction of solar heater.
Construction of solar concentrations.
Construction of glass thatched houses.
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UNIT SIX
POWER AND MACHINES
POWER
Is the rate of doing work in a unit time.
The SI unit is joules per second (J/s) also called watt (W).
IJ/s = 1 watt
Watt is the rate of transfer of energy of 1 joule in one second.
RELATIONSHIP BETWEEN POWER AND VELOCITY
Work done = force x distance covered.
Power =
Power =
But
= velocity.
Therefore, power = force x velocity
P = Fv
Exercise
A force of 100N drags a box at a constant velocity of 5m/s. What is the power of the
source of the force?
A student of mass 45kg runs up a flight of 40 steps in a stair case each 15cm in 12
seconds. Find the power of the student.
A car engine developed a 24kw while travelling along a level road. If there was a
resistance of 800N due to friction, calculate the maximum speed attained.
MACHINES
A machine is any device that makes work to be done easily.
Is any device that facilitates a force applied at one point to overcome another force at
a different point in the system.
TERMS USED IN MACHINES
Mechanical advantage
is the ratio of the load and applied force
Mechanical advantage =
M.A. =
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Velocity ratio
Is the ratio of velocity of effort and velocity of the load
Velocity ratio =
Velocity of effort =
Velocity of the load =
Velocity ratio =
Efficiency of machine
Is how best is it to use a machine.
Is measured in percentages.
Is the ratio useful energy output multiply by 100 and energy input.
Efficiency =
But useful energy output = load x distance move by the load and
energy input = effort x distance moved by the effort
efficiency =
x
But
= M.A. and
=
Therefore, efficiency =
NB
No machine is 100% efficiency.
Some energy is lost when the machine overcomes frictional force in movable part of
the machine and surface.
THE EEFECT OF FRICTION ON MECHANICAL ADVANTAGE, VELOCITY
RATIO AND EFFICIENCY OF A MACHINE.
Mechanical advantage (M.A.)
When the frictional force is high, the effort applied is also high.
This reduces the mechanical advantage of a machine.
Velocity ratio
Is not affected by the friction.
The angle at which the machine is does affect the velocity ratio.
Efficiency of a machine
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Is affected by the friction.
Decrease in M.A. also reduces the efficiency of the machine.
increased friction lowers the efficiency of the machine.
Exercise
A machine whose velocity ratio is 8 is used to lift a load of 300N. The effort required
is 60N.
a. What is the mechanical advantage of the machine?
b. Calculate the efficiency of the machine.
An effort of 250N raises a load of 900N through a 5m in a machine. If the effort
moves through 25m, find
a. The total useful work done in raising the load.
b. The work done by the effort.
c. The efficiency of the machine.
Calculate the efficiency of a machine if 8000J of work is needed to lift a mass of
120kg through a vertical height of 5m.
TYPES OF MACHINES
Force multipliers
Are those that allow a small effort to move a large load
Levers are good example such as
Screw jack of a car
Hydraulic press
Hydraulic jack
Hydraulic breaks
Distance or speed multipliers
Are those which multiply the distance or speed.
Inclined planes and pulleys are good examples such as
Bicycle gears
Car gears
Incline planes
Pulley systems
EXAMPLES OF MACHINES
Inclined planes
Pulleys
Levers
INCLINED PLANES
Is a slope or ramp that enables us to raise a heavy load to a certain vertical height.
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Suppose the load of mass 200kg is pulled along an inclined plane above by the force
(e) of 1500N, distance (d) of 5m and height (h) of 3m, calculating
a. Mechanical advantage of the machine
M.A. =
=
= 1.33
b. Velocity ratio of the machine
V.R. =
=
= 1.67
c. Efficiency of the machine
Efficiency =
=
80%.
PULLEY
Is usually a grooved wheel or rim.
Pulleys are used to change the direction of force.
TYPES OF PULLEYS
Single fixed pulleys
Has fixed support which does not move.
Either the load or effort does move.
The tension in the rope is the same throughout.
The load is equal to the effort if these is no loss of energy (friction)
The M.A. is therefore 1
Application of fixed pulley
Raising of flag
Raising bricks up by builders
Effort
Load d h
Fixed point
Tension (T)
Effort (e)
Load (L)
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Raising water from the well
Single moving pulleys
The total force supporting the load if given by the tension (T) plus the effort
(E).
Tension (T) force is equal to twice the effort (2E).
The load (L) is equal to twice the effort (2E).
M.A. =
=
= 2
The effort moves twice the distance moved by the load.
V.R. =
=
= 2
Since M.A = V.R, the pulley system has 100% efficiency if there is no
frictional force.
Block and tackle pulleys
Consists of two pulley sets.
One set is fixed while the other set is allowed to move.
Pulleys are usually assembled side by side in a block or frame on the same
axle.
The pulleys and ropes are called the tackle.
T E
L
T
1
T
2
E T
1
E
T
2
T
3
T
4
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For each of the pulleys above,
For a single fixed pulley, L = T = E
E = L
For a single movable pulley,2T = L, and T = E
2E = L
For the block and tackle, 4T = L, T = E
4E = L
NOTE:
In a perfect pulley system, the mechanical advantage is equal to the velocity ratio and
both are equal to the number of sections of the string supporting the load.
The weight of the block in the lower section of the system and fraction in the pulley
reduces the mechanical advantage of the system.
Velocity ratio of a pulley system is numerically equal to the number of string sections
supporting the load.
LEVER
Is a rigid bar capable of rotation about a fixed point called pivot of fulcrum.
Are three types of levers depending on the position of the pivot with respect to the
load to be overcome and effort applied.
Pivot
Is between the load and the effort.
Crowbar
A pair of scissors
Claw hammer
Pliers
See-saw
spanner
Load
Is between the pivot and effort.
Wheel barrow
Bottle opener
Effort
Is between the pivot and the load.
Fishing rod
Tweezers
Forceps
L E
Load distance(arm)
effort distance (arm)
pivot
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PRINCIPLES OF MOMENTS
A moment of force about a point is the product of the force and perpendicular
distance from the point to the line of action of the force.
PRINCIPLES OF LEVERS
States that sum clockwise moment at a point is equal to the sum of anti-clockwise
moment at the same point of equilibrium.
MECHANICAL ADVANTAGE OF A LEVER
Taking moment about the pivot as
Load x load arm = effort x effort arm
=
But
= mechanical advantage
M.A =
=
V.R. =
Since effort arm is usually greater than load arms, levers have mechanical advantage
greater than 1.
Examples of levers and their uses
Bottle openers, lid openers used to open bottle tops and lids respectively.
See saw and beam balance used for playing games and comparing weights of
different objects.
Hinges are used in closing and opening of the doors, windows etc.
Spanners are used in tightening and loosening bolts and nuts.
A pair of scissors or garden shears used in cutting etc.
Crowbar used in moving heavy loads.
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UNIT SEVEN
ELECTROSTATICS
ELECTROSTATICS
Is the study of branch of physics that deals with phenomena due to attraction or
repulsion of electric charges.
ELECTROSTATIC CHARGING BY RUBBING
When polythene stripe is rubbed against silk, it acquires attractive property.
This is because it has been charged by friction.
It can attract thin stream of water, small pieces of paper, and tiny pieces of cloth.
This implies that bodies can be charged by rubbing each other.
These charges cannot be move from one point to another.
These are static charges.
TYPES OF STATIC CHARGES
Positive charges
Are charges which the body gains when it loses electron(s).
Silk loses electron(s) when rubbed against the polythene.
Negative charges
Are charges which the body gains when it gains electron(s).
Polythene gains electron(s) when rubbed against silk.
SOURCES OF ELECTROSTATIC CHARGING
Charges can be gained when materials
Gain electrons
Polythene gains electron(s).
Lose electrons
Cloth loose electron(s).
TAKE NOTE
The excess negative charges on one body is equal to the excess positive charges on
the other body. i.e. no charge have been created.
During the rubbing process, materials may acquire either negative or positive charges.
The quantity of charge produced in some cases may be small and in some cases the
charges may escape before they are defected. A dry atmosphere and a clean dry state
of the body are essential for holding the electrical charges.
THE LAW OF CHARGES
Like charges repel and unlike charges attract.
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CONFIRM THAT A BODY IS CHARGED
Bring charged bodies close together.
If they attract, they have different types of charges.
If they repel, they have the same type of charge.
No attraction, they are neutral.
SI unit for charge is coulomb (C), named after a famous scientist called Charles
Augustin de Coulomb (1736 – 1806)
EARTHING
This means to neutralise a charged body.
Low charges can be earthed by touching the charged body with our hands.
High charges should be connected to the thick metal rod.
The metal plate is connected to the earth.
This conducts excess electrons flow from the plate to the earth.
If a positively charged plate is connected to the earth, the electrons from the earth
move to the plate and neutralise the deficiency of electrons.
ELECTRIC FIELD AND ELECTRIC FIELD PATTERNS
ELECTRIC FIELD
Is indicated using arrow lines.
The arrow indicates direction of electric field and the tail is where the electric field
comes from.
These line which show direction of movement of charges are called electric field lines
or electric line of force.
Number of field lines indicates the strength of charge. The more the lines, the high the
charge.
These electric field lines are also called field patterns or flux patterns.
PROPERTIES OF ELECTRIC LINES OF FORCE
Lines of forces start at 90
o
from the positive charge and end on the negative charge at
90
o
.
No two lines of forces can ever cross each other.
The field lines can contract or expand so that they never intersect each other.
FACTORS AFFECTING THE MAGNITUDE OF THE FORCE BETWEEN TWO
CHARGED BODIES
Quantity of charge
The greater the quantity of charge, the greater the force between the body.
Distance of separation
The greater the distance, the smaller the force.
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LEAF ELECTROSCOPE
Is an instrument used for detecting and testing small electric charges.
Was invented by Abraham at the end of 18
th
century.
The electroscope should be charged before being used.
If uncharged, it can detect the presence of charge but not indicating the type of charge
present.
If the electroscope is charged positively, the leaf electroscope leaflets can attract each
other if negative charges are present and repel if positive charges are detected.
If charged negatively, positive charges can make leaflets attract and negative charges
can make leaflet repel.
METHODS OF CHARGING
Contact
Is done when the charged body is contact with the body to be charged.
The alignment of domains point to one direction.
The body becomes charged.
Induction
The charged body is brought close to the body to be charged.
The alignment of domains point to one direction.
The body becomes charged.
USES OF LEAF ELECTROSCOPE
Detecting presence of charges.
Identifying type of charges.
Distinguishing between conductors and non-conductors.
EFFECTS AND APPLICATION OF ELECTROSTATICS
One gets a shock.
The car that has been left so long on the sunlight becomes charged and upon
touching the knob one gets shock.
When one is shocked, the car’s charges become neutralised.
Brass disc or cap
Insulator
Brass rod
Gold leaf
Earth metal case
Dry air
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The discharging of the charges is mostly done by the chain connected to the
vehicles.
The charges pass through the chain to the earth.
Cleaning the mirror with a dry cloth makes both the mirror and cloth become charged.
This makes dust particles to be attracted on the surface of the mirror.
Painting of cars using spray gun, the paint receives a positive charge which makes it
to be attracted to the car body.
Removal of dust and smoke particles from the chimney uses electrostatic attraction.
This reduces the air pollution which is a health hazard.
Electrostatic induction is used in photocopying machines.
The rubbers insulator called conductive rubber is used to make aeroplane tyres. This
reduces the risk of an explosion during refuelling the aircraft.
LIGHTNING ARRESTOR
Is used to prevent tall buildings and towers against the destructive effect of lightning.
Is made up of the metal rod attached to the metal plate and buried deep in the ground
one end while the other end point up above the building to conductelectrons down the
earth.
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UNIT EIGHT
LIGHT
LIGHT
Is a form of energy that enables us to see the surrounding objects.
Is not visible but its effect is felt by eyes.
It travels in a straight line.
TERMS USED IN STUDY OF LIGHT
Luminous bodies
Are bodies which emit light on their own.
Are also known as self-luminous bodies.
Examples include
Sun
Torch
Fire
star
Non-luminous bodies
Are bodies which have no light of their own.
Are visible in the presence of some luminous bodies.
Examples include
Moon
Polished bodies
Optical medium
Are substances through which light can pass.
Are three types of them
Transparent bodies
The ones through which light pass with no problem e.g.
window glass.
Translucent bodies
The one through which light passes partially e.g. some plastic
containers.
Opaque bodies
The ones through which light cannot pass e.g. clay pot.
A ray of light
Is the path through which light travels in a medium.
Is shown using a single arrow line.
A beam of light
Is a collection of rays of light.
These can be
Parallel beam of light
Rays which point to one direction but do not meet.
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Convergent beam of light
rays which originate from different points and meet on
one focal point.
Divergent beam of light
Rays originate from one point to different directions.
FORMATION OF SHADOWS AND ESCLIPSES
SHADOWS
Is a shade cast by an object blocking the direct ray of light.
FORMATION OF SHADOW WITH A POINT SOURCE
When light is allowed to pass through a small opening blocked by opaque object, the
path of light is also blocked.
Forms a total darkness on the screen.
This region of a complete darkness is called umbra.
FORMATION OF SHADOW WITH AN EXTENDED SOURCE OF LIGHT
When light is passed through a large opening blocked by opaque object, forms an
extended source of light.
This forms two types of shadows on the screen.
A total darkness is formed at the middle of the screen called umbra.
Surrounding the umbra, there is partial darkness called penumbra.
Screen
Small hole opaque body
Source of Shadow
light
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ECLIPSE
Is when light is blocked or cut off from region of observation.
Are two types of eclipses
Solar eclipse
Lunar eclipse
SOLAR ECLIPSE
Happens when the moon is between the sun and earth.
The shadow of the moon is formed on the earth. The shadow is called eclipse or
eclipse of the sun.
Depending on the position of the sun, some parts lie in the region of umbra while the
other parts lie on the region of penumbra.
Total eclipse lies in the region of umbra while partial eclipse lies in the region of
penumbra.
LUNAR ESCLIPSE
The moon is non-luminous object.
Can be seen only when light from the sun falls on it.
What is seen is only the shape of the lighted portion.
The earth is between the sun and moon.
This is called lunar eclipse or eclipse of the moon.
Penumbra
Umbra
Moon Earth
Umbra
Penumbra
Sun
Sun Earth Moon
Umbra Moon
Penumbra
Moon
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PINHOLE CAMERA
Is an instrument an instrument that can be used to show that light travels in a straight
line.
Form an image smaller than the object.
The image is upside-down .
Forms a real image.
MAGNIFICATION
Is how big or small the image is as compared to the object.
Is the ration of the height of image and the height of the object.
Magnification =
=
M =
=
REFLECTION
Is the bouncing off of light.
Are two types of reflections namely
Regular reflection
When the light strikes a smooth surface.
The parallel rays of light form parallel reflected rays of light.
Diffuse reflection
When the light strikes a rough surface.
Parallel rays of light make scattered reflected rays of light.
Parallel rays parallel reflected rays
Parallel rays scattered rays
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PLANE MIRROR
Is a thin glass plate coated with silver on one side and a protective layer on the other
side.
Can reflect light rays.
LAWS OF REFLECTION
Incident ray, reflected ray and normal ray lie in the same plane
The angle of incident (i) and angle of reflection (r) are equal.
IMAGE FORMATION FOR A POINT OBJECT
Two rays can be used to locate the position of the image using plane mirror.
The reflected ray and incident rays meet at a point.
This point of contact is the position of the image.
The image is called virtual image and cannot be projected on a screen.
Image distance from the mirror is equal to the object distance from the mirror.
OM = IM
IMAGE FORMTION FOR AN EXTENDED OBJECT.
If an object is extended in front of a vertical plane mirror, the image formed is erect.
The size of the image is the same as the size of the object.
The image is upright.
Incident ray Normal line Reflected ray
I r
Mirror
IM
OM
Point object
Image
Object Mirror
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The image formed is lateral inversion image.
This is the image whose left hand side is seen to be the right hand side.
CHARCTERISTICS OF IMAGES FORMED BY PLANE MIRRORS
The size of the image is equal to the size of the object.
The image is erect.
The image is virtual.
The image is lateral inverted.
The image distance is equal to the object distance and is behind the mirror.
ROTATION OF THE PLANE MIRROR
For the same incident ray, the angle of rotation of the reflected ray is twice the angle
of rotation of the mirror.
PARALLEL MIRRORS
When the object is placed between two parallel mirrors, the image formed on one
mirror is reflected to form another image on the other mirror.
That image can also form another image on the other mirror.
WORKING OUT NUMBER OF IMAGES FORMED TWO MIRRORS AT AN
ANGLE
Number of images formed (n) =
- 1
If the angle is 60o, n =
- 1
= 6 – 1
= 5
APPLICATION OF REFLECTION OF LIGHT
In periscope
Is an instrument for seeing distant objects.
Two mirrors are placed parallel to each other.
This makes the image formed on one mirror forms an image on another
mirror.
Image
Object Eye
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In kaleidoscope
For production of series of beautiful images.
REFRACTION OF LIGHT
Is the bending of light after crossing substances of two different densities.
Thin rod dipped into water appears to be bent at the water surface.
Pool waters appears to be shallow than its real depth.
When light is passed from denser substance to the less dense substance, it bends away
from the normal line.
When it is passed from less dense to denser, it bends towards the normal line.
So, reflection can be defined as the change of direction or bending of light when it
travels from one medium to another.
MONOCHROMATIC LIGHT
Is the one that has a single frequency of single wavelength.
White light is not monochromatic light because it is made up different colours.
DISPERSION OF WHITE LIGHT
White light can be dispersed into a light spectrum.
Dispersion is the splitting of white colour into its constituent colours.
The colours starting from top are
Red
Orange
Yellow
Green
Blue
Mirror Object
Eye Mirror
Air
Water
Air
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Indigo
Violet
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UNIT NINE
INTRODUCTION OF NUCLEAR PHYSICS
NUCLEAR STRUCTURE OF AN ATOM
Neutron Shell (orbit)
Proton
Electron Nucleus
NUCLEUS
Is the most inner part of an atom.
Makes the mass of the whole atom.
Is comprised of protons and neutrons.
NEUTRONS
Are uncharged particles in the nucleus of an atom.
PROTONS
Are positively charged particles in the nucleus of an atom.
PROTONS AND NEUTRONS
Number of protons and number of neutrons together make up atomic mass.
Protons alone gives the atomic number.
NUCLEAR NOTATIONS
Atomic number is denoted by a symbol A.
Atomic mass is denoted by a symbol Z.
ISOTOPES
These are atoms of the same element with different atomic mass but same atomic
number.
N
P
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This is because they have different number of neutrons in their nuclei.
Hydrogen has the following isotopes
RADIOISOTOPES
Are isotopes as a result of spontaneous disintegration of an atom to attain stability.
RADIOACTIVITY
Is the spontaneous disintegration of an atom to attain stability.
Is the emission of particles or electromagnetic radiations by nuclei.
Is also known as radioactive decay.
TYPES OF RADIOACTIVE DECAY
Radioactivity results into three forms of subatomic particles.
These include
Alpha particles ()
Beta particle ()
Gamma ray ()
ALPHA PARTICLES ()
A nucleus eject two protons.
These reduce the mass of an atom.
It results into transformation of the element into a different element.
The particle is helium nucleus (
) in nature.
The atomic mass of a parent nucleus decreases by 4 while the atomic number
decreases by 2.
As you can see above, the particles is positively charged.
This charge makes it to deflect magnetic field.
They deflect less because they have large masses.
These have less penetrating power.
They cannot penetrate the skin.
+
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These are very dangerous when they are injected or inhaled.
Their penetrating power is one.
BETA PARTICLE ()
A negatively charged particle identical with electron is produced i.e
.
You recall that nuclear structure of an atom shows no electron in the nucleus.
These electrons are produced in the nucleus when a neutron. Changes into a proton.
During beta decay, the mass number of a radioactive element remains unchanged,
while the atomic number increases by one unit.
The particle moves at nearly the speed of light i.e. 3x10
8
m/s.
It has greater penetrating power than alpha.
It has the penetrating power of 100.
The particle is negatively charged.
It has almost no mass (negligible mass).
It is deflected towards the positive pole of a strong magnetic field.
The deflection is much greater than that of alpha.
GAMMA RAY ()
Sometimes the nucleus can remain unstable even after emitting the alpha or beta
particles.
It possesses a lot of energy after the decay.
It emits a ray of light to get rid of the excess energy.
is unstable. It gains stability by the loss of gamma rays.
This does not make any change of both atomic number and atomic mass.
Gamma rays are not particles.
They do not possess any charge.
These do not deflect in the presence of the electric and magnetic field.
They have the penetrating power of 10,000.
DEFLECTION SUMMARY
+
+
+
+
_ _ _ _
+ + + +
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PENETRATING POWER SUMMARY
NUCLEAR STABILITY
The nucleus of an atom contains many protons and neutrons.
Since protons carry similar changes, they repel each other.
This repulsion is due to short distances between the protons.
The protons are bound by a powerful localised force with the help of the neutrons
which balance the opposing forces of the protons.
This force is called nuclear binding force.
This force is limited to number of protons coexist with the neutrons in a nucleus.
If the number is greater, the nuclei break on their own to achieve stability.
This leads to the radioactivity.
HALF-LIFE AND RATES OF DECAY
Half-life is time it takes for half the original amount of isotope in a given sample to
decay.
It is time taken for a substance to decay half of its mass.
It is formed by N =
where N is radioactive nuclei present, No is number of
nuclei present at time t, λ is decay constant and t is time taken.
Half-life is indicated as T
½.
the relationship between half-life and decay constant is T
½ =
.
USES OF RADIOISOTOPES
generation of atomic energy
nuclear fission
is the splitting of heavy nucleus into two lighter nuclei of
approximately the same size.
Slow moving neutrons are used to strike nuclei of less stable heavy
elements.
Sheet of paper Sheet of aluminium Lead metal block thick
2cm thick
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As shown above the process involves the release of energy.
nuclear fusion
it is the combining of two small nuclei to form heavy nucleus which is
unstable.
Some mass is converted into large amount of energy.
Carbon dating
Carbon 14 is used to estimate when a certain fossil could have been existing.
Medical use
Cobalt 60 is used to curb cancer.
Gamma radiations penetrate the body and kill the cancerous cells.
Gamma radiation is used to sterilise surgical instruments.
Used for treating goitre
For diagnosing of circulatory problem
Treating tumours
Industrial use
Radioactivity is used in packaging industries
Tea factory uses such isotopes to detect whether the tea leaves are
packed correctly or not.
Detecting of oil leaks in pipe lines. Short-lived radioisotopes are introduced in
the pipe to be detected from where the pipe is broken.
Agricultural use
Tracing fertilizer action.
Sterilising male insects so as to reduce population.
Obtaining information about animal and plant nutrition.
DANGERS OF RADIOISOTOPES
Can cause skin burn.
Can cause cell ionisation in the body.
Can cause uncontrolled growth of tissue and cancer.
Can affect genetic make-up that can result into deformed babies born.
Can result into emission of enormous amount of energy in the form of heat.
Causes redness of the skin.
Blistering and sores.
+
+
+ Energy
+
+
+ Energy
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DETECTION OF RADIATIONS
Photographic plate
When exposed to radiations, radiations penetrate the plate.
Penetration exposes the surface.
Electroscope
Can be made using money clips and the paper inside the cigerate packet.
Air molecules become charged by alpha ions.
This discharges the electroscope.
The gold leaf repels
Spark Counter
Device for detecting radiations.
Consists of a fine wire stretched below a piece of wire gauze.
A high voltage between the gauze and wire is adjusted until it is almost but not
quite sparkling.
The ionising power of the radiations would then make the air ionized
becoming conductive.
Sparks are then produced under high voltage.
Geiger-Muller Tube
Consists of a long tube containing inert gas at low temperature.
It has a protective cover for the mica window.
The tube has anode as well as cathode.
The tube is connected to an amplify.
When a radioactive source is brought from the source penetrate it and ionises
the gas inside.
Brass disc or cap
Insulator
Brass rod
Gold leaf
Earth metal case
Dry air
wire gauze
High
voltage Spark
source Wire
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This induces a current.
Whenever current flows in the amplify, a click is heard.
Cloud Chamber
Device used to detect ionizating radiations.
Consists of closed container filled with supersaturated vapour.
When the ionizing radiation passes through the vapour, the vapour leaves a
trail of charged particles (ions).
Ions saves as condensation centre for vapour.
Scintillation Counter
Is also a device for detecting and measuring radiations by means of tiny
visible flashes produced by the radiations when it strikes a sensitive substance
called phosphor.
The individual flashes are caused by absorption and re-emission of radiation
by the phosphor.
This detects only gamma rays because it is very thick.
PRECAUTIONS MEASURES
Handle radioactive substances with forceps never with bare hands.
Cover any cut on the skin before handling radioactive substances.
Do not point radioactive substances towards a human body.
Return radioactive substances to their container soon after use and store them in lead
container.
Always check for radiations after experiment.
Do not stay long in a region of radioactive substances.
If possible, use lead shielding when in a region of radioactive substances.
Thin wire Mica window
Amplifier
Geiger Muller Tube
Protective cover
